This invention relates generally to slip or pull sheets, and specifically pertains to a reinforced pull sheet that incorporates structural tapes at strategically internal locations so as to withstand the excessive forces imposed upon it during repeated usage.
Pull sheets have long been utilized in the prior art, generally identified as slip sheets, and these sheets are designed of various types of material, frequently paperboard, and are intended to function as a replacement for the more expensive and cumbersome wood type pallets used for supporting the heavy load of stacked material. These slip sheets are of a size to just accommodate the supported load, and generally have dimensions somewhat equivalent to the dimensions of the fork or plate forming the platform for the forklift truck that is utilized for transferring this load throughout various locations, whether about the plant, or onto a truck or railroad car. The pull sheets generally should withstand the rigors of certain forces, since they are initially grasped by means of the gripper bars of the truck that clamp onto an edge of the slip sheet, and which pull the same and its load onto the truck platens, or forks, but at the same time, after the truck has maneuvered the load to its intended location, the same slip sheet is then pushed off of the truck forks for other disposition.
In many instances, these slip sheets of the prior art have only been capable of single usage, facilitating the transfer of a load from its initial stack to its appointed destination, and since the loads absorbed are frequently excessive, the dock workers normally utilize two such corrugated sheets to sustain a single stacked load. Thus, this doubles the cost for this aspect of hauling packaged materials to and from a plant.
Various reinforcing means have been given some consideration in the prior art, but not for use in conjunction with the pull sheet, and such reinforcing means include fiberglass, plastic, or other type of reinforcing string or tape, generally incorporating the hot melt feature, and which tape is applied either to the surface of the paperboard, or the interior surface of the liner, and fabricated into the board during its corrugation. Such formed board has found usage particularly as a means for forming reinforced cartons or boxes, particularly of the type that may be subjected to loading of rather heavy and bulky materials, and which have a tendency to bulge the sides of the cartons and eventually cause their tearing. It is to be noted, though, the type of tapes or strings heretofor contemplated in the art, for this particular purpose, have always been of the more man-made fiber type, whether as fiberglass, or a polymer, and are not capable of being recycled with the paperboard after its usage. In fact, such man-made fibers within the board has presented a problem and a detriment to those paper companies that make it their business to augment their paper stock through the use of recycleable fibers.
It is, therefore, the principal object of this invention is to provide a pull sheet formed of corrugated board and which includes a reinforcing tape that furnishes sufficient structural strength to the sheet to allow for its individual usage in supporting the conveyance of a load by a forklift truck.
Another object of this invention is to provide a pull sheet incorporating recycleable reinforcing tapes that can be repeatedly used, or recycled, after its deterioration beyond usage.
Another object of this invention is to furnish a pull sheet that incorporates a series of conveniently arranged fold lines that facilitates the truck gripping of the pull sheet and its supported load from a variety of directions during the load transfer.
Yet another object of this invention is to provide designed means within a pull sheet forming a plurality of grippable edges, and which edges can be conveniently folded with respect to each other without any mutual interference due to the intersection of their fold lines.
Still another object of this invention is to provide for integral reinforcement of a pull sheet by arranging reinforcing tapes at the edge and central location where the heaviest tearing forces are most frequently encountered.
These and other objects will become more apparent to those skilled in the art upon reviewing the summary of this invention, and upon undertaking a study of the description of its preferred embodiment, in view of the drawing.